Currently there are weighing machines with a transport system that continually moves carriages, to which buckets are coupled, along a closed path. A known type of machine comprises a series of work stations distributed along the path followed by the carriages, and by extension the buckets coupled to the carriages, such as a loading station where fruit is fed into the buckets; a weighing station where the fruit contained in each bucket is weighed; and an emptying or unloading station where the buckets are emptied.
In so-called combination weighing machines, several buckets are attached to the same support, and at the emptying station there is a selective emptying of the buckets whose total fruit weight is closest to a predetermined value. A weighing machine of this type is described in patent document EP 0982570.
The weighing operation in the weighing station is carried out without interrupting the forward movement of the carriages; in other words, without stopping the transport of the buckets.
To carry this out, in EP 0982570 it is suggested that the buckets are coupled to the carriages in a way that allows the buckets to be raised with respect to the associated carriage, but without becoming mechanically separated. This means that the bucket can adopt, with respect to the carriage, a supporting position in which the weight of the bucket rests upon the carriage, and a weighing position, in which the bucket is slightly raised with respect to the carriage.
This coupling allows the buckets in the weighing station to circulate by sliding along the weighing platform that is connected to a loading cell without ceasing to be transported by the associated carriage. On the machine according to EP 0982570, the buckets have flaps and a front extension that allow the bucket to support itself on the weighing platform in slide mode.
A similar solution is described in patent document EP 0803716, in which the buckets are assembled over a roller which is intended to support them on a weighing platform of the weighing station as the bucket is transported along the weighing station.
An aim of the invention is a more precise machine, which ensures better weighing accuracy than that of known machines.
Another aim of the present invention is to improve weighing accuracy without affecting the speed of the machine. This would prevent the transport speed of the buckets from slowing down and the weighing operation would not be the bottleneck of a machine that is incorporated, in addition to the weighing station and the loading and unloading stations of the upstream and downstream products, respectively, at the weighing station.
Other aims of the invention are to improve or simplify the maintenance tasks of the known machines. For example, during machine operation, dirt, particles or grease can fall onto the weighing platform and alter the accuracy of weight measurement. Furthermore, access to the weighing platform and other essential components of the platform, such as the loading cell, are arranged on the inner side of the carriage path when the weighing station is located on the straight top section of the closed path that make the carriages move.